FOOD QUALITY AND STANDARDS – Vol. III - Additives and Contaminants - Natalia Cicic-Lasztiy
ADDITIVES AND CONTAMINANTS
Natalia Cicic-Lasztiy
Hospital Heim Pal, Budapest, Hungary
Keywords: antibiotics, anticaking agents, antimicrobial agents, antioxidants, dioxin,
emulsifier, emulsion, flour improvers, food additive, food contaminant, mycotoxicosis,
mycotoxin, PAH, PCB, pesticides, pesticide residues, preservatives, veterinary drugs,
veterinary drug residues
Contents
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1. Food Additives
1.1. Antimicrobial Agents
1.1.1. Sulfites and Sulfur Dioxide
1.1.2. Benzoic Acid and its Derivatives
1.1.3. Sorbic Acid
1.1.4. Other Compounds
1.1.5. Antibiotics
1.1.6. Future Trends in Use of Antimicrobial Agents
1.2. Antioxidants
1.3. Emulsifiers
1.4. Gelifyers and Thickeners
1.5. Other Additives
2. Contaminants
2.1. Mycotoxins
2.1.1. General
2.1.2. Aflatoxins
2.1.3. Fusarium Toxins
2.1.4. Fumonisins
2.1.5. Other Mycotoxins
2.2. Residues of Pesticides and Herbicides
2.3. Residues of Veterinary Drugs
2.4. Other Chemical Contaminants
2.4.1. Chlorinated Dibenzo-p- Dioxins, Dibenzofurans and Biphenyls
2.4.2. Polycyclic Aromatic Hydrocarbons (PAHs)
2.4.3. Contamination with Toxic Metals
Glossary
Bibliography
Biographical Sketch
Summary
Different definitions of the term ‘food additive’ are used. One of the simplest definitions
is: Any substance added to a food to give it desired property. According to FAO/WHO
Codex Alimentarius, food additive means any substance intentionally added to food for
technological purposes and/or to improve appearance, flavor, color, texture, storage
properties or any other characteristic property of food. The term does not include
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FOOD QUALITY AND STANDARDS – Vol. III - Additives and Contaminants - Natalia Cicic-Lasztiy
substances added to food for maintaining or improving nutritional quality of food; for
which the term “enrichment” or “fortification” is generally used.
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Although some types of additives (salt, spices, natural coloring materials) were used
since hundreds or even thousand years ago, the wide use of chemical additives is
connected with development of modern food industry. Bearing in mind the big number
of food characteristics to be influenced by additives and also a lot of technological
requirements, the number of additives used at this time is high (e.g. the regulations of
European Union permit the use of more than 600 different additives). From regulatory
standpoint, each of the food additives must provide some useful and acceptable function
or attribute to justify its usage. Among generally acceptable functions the improved
preservation quality, improvement of functional properties, processing facilitation, and
enhanced consumer acceptance may be mentioned. Concerning the food safety the
following criteria should be kept in mind:
1. An additive must not have any harmful health effect
2. It must not allow the use of unfit raw material
3. Its use must not make possible the employment of careless and imperfect methods of
manufacture
4. It must not retard the action of digestive enzymes
5. It must have no tendency to decompose within the body into substances which have a
greater toxicity than that of the additive itself
6. It should lend itself to simple methods of determination and thus simplify the control
of food.
Although the permitted additives were thoroughly controlled, the tendency today is the
reduction of the use of additives in food production. Usage of additives is discouraged
where similar effects can be obtained by economical and good manufacturing practices.
The additives used in food processing may be divided in two groups: (i) naturally
occurring compounds or additives isolated from natural sources and (ii) synthetic
chemicals. The chemistry of first group is treated in corresponding chapters dealing
with main nutrients (proteins, lipids, carbohydrates) and minor food constituents
(vitamins, minerals, color compounds, flavor compounds). In this chapter the main
synthetic additives (antimicrobial agents, antioxidants, and other chemicals) will be
overviewed.
The second part of this chapter is devoted to the main groups of contaminants. The
mycotoxins (aflatoxins, fusarium toxins) residues of pesticides, veterinary drugs,
dioxins, polycyclic aromatic compounds and toxic metals will be overviewed.
1. Food Additives
Additives used in food processing may be divided into two groups: (i) substances
occurring in the nature or isolated from the natural sources and (ii) synthetic chemicals.
Keeping in mind the fact that natural additives were discussed in the framework of
corresponding food constituents (e.g. emulsifiers in Lipids; alternative sweeteners, color
and flavor compounds in Aroma and Color Compounds) in this chapter primarily the
©Encyclopedia of Life Support Systems (EOLSS)
FOOD QUALITY AND STANDARDS – Vol. III - Additives and Contaminants - Natalia Cicic-Lasztiy
synthetic additives will be treated.
1.1. Antimicrobial Agents
Antimicrobial agents (often referred to as preservatives) may be defined as substances
inhibiting the growth of microorganisms or killing them. They play the main role in
food spoilage chemical preservatives with antimicrobial properties in preventing
spoilage of foods (See also Spoilage and Preservation of Foods). In the framework of
this chapter a short overview will be given of frequently used chemicals.
1.1.1. Sulfites and Sulfur Dioxide
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Sulfur dioxide has been used for long for preservation of fruits, vegetables and wine. In
addition to gaseous sulfur dioxide, sodium – and potassium sulfites (metabisulfites,
bisulfites) are also employed for such purposes. It has been shown that sulfur dioxide is
most effective as an antimicrobial agent in acid media. That is why it is frequently used
in preservation of acidic foods such as major part of fruits.
Sulfur dioxide and sulfites are metabolized to sulfate and are excreted in the urine
without any obvious pathological results at the concentration level used generally in
food processing. The maximum level of free and bound (sulfuric acid and sulfites may
react with some food constituents e.g. sugars) are regulated and controlled. It may be
also mentioned that some people e.g. asthmatics are sensitive to sulfur dioxides and
their derivatives.
1.1.2. Benzoic Acid and its Derivatives
Benzoic acid has been widely employed as an antimicrobial agent in foods. It is
primarily used for preservation of acid foods such as fruit juices, carbonated beverages,
pickles and sauerkraut because the antimicrobial effect is connected with undissociated
form of benzoic acid. Benzoic acid has been found to cause no deleterious effects in
humans when used in amounts limited by food regulations.
Alkyl esters of benzoic acid, named as group parabens, are used in baked foods, soft
drinks, beer, jams, jellies, and pickles. Parabens exhibit a low order of toxicity to
humans and are excreted in the urine after hydrolysis together with benzoic acid.
1.1.3. Sorbic Acid
Sorbic acid (Fig. 1) and its sodium and potassium salts are widely used to inhibit mold
and yeasts in a wide variety of foods, including cheese, baked foods, fruit juices, wine,
and pickles. In general, sorbic acid is more active in acid media, it is effective up to
pH=6.5.
Figure 1: Sorbic acid
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FOOD QUALITY AND STANDARDS – Vol. III - Additives and Contaminants - Natalia Cicic-Lasztiy
1.1.4. Other Compounds
In addition to frequently used chemicals mentioned above, a lot of other compounds are
known which are used for preservation purposes. Propionic acid has found extensive
use in the bakery field, where it not only inhibits molds effectively but also is active
against the ropy bread organism, Bacillus mesentericus. The preservation of foods with
acetic acid (vinegar) dates back to antiquity and at present is also widely used.
Also used in foods are sodium acetate and potassium acetate. Acetic acid is also used in
such foods as catch-up, mayonnaise, and pickles, where it serves dual function of
inhibiting microorganisms and contributing to flavor.
1.1.5. Antibiotics
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Antibiotics, a large group of antimicrobial agents produced naturally by a variety of
microorganisms, are widely used in medicine. The success of antibiotics in controlling
pathogenic microorganisms in living animals has led to extensive investigations into
their application in food preservation. A limited number of antibiotics (nisin, chlortetracycline, and oxy-tetracycline) are in use, under restricted conditions, in food
industry. For example, dipping whole poultry carcasses into solutions of chlortetracycline or oxy-tetracycline is permitted. This increases the shelf life of the poultry,
and residual antibiotics will be destroyed by usual cooking methods.
1.1.6. Future Trends in Use of Antimicrobial Agents
Due to increased requirements concerning food safety, there is a general trend in food
industry that efforts are made to decrease the use of any antimicrobial chemicals in food
processing. Efforts are now focused on reduction and future ban of use of antibiotics.
Bearing in mind that use of antibiotics in animal husbandry may result occurrence of
antibiotic residue in food of animal origin, efforts are extended to reduction of use of
antibiotics also in animal husbandry.
The reduction of use of other traditional antimicrobial chemicals is a trend also in food
industry by development of new processing- and storage technologies and search for
natural plant extracts, constituents with antimicrobial action. Such trend is stimulated by
facts that in some cases, due to modern research techniques, a harmful effect of some
earlier used compounds was detected and their further application is not permitted.
1.2. Antioxidants
As it is well known, the oxidative deterioration of edible fatty materials is a serious
problem because it leads to a decrease in organoleptic quality and nutritional value.
Although excluding of oxygen, storage in darkness, avoiding the use of metallic
containers may significantly reduce the undesired oxidative changes; in practice
additives with antioxidative activity are widely used. Antioxidants are natural and
synthetic substances that can delay the onset or slow the rate of oxidation of oxidizable
materials. Hundreds of natural and synthetic compounds are known which possess
antioxidative properties; however, a limited number of such substances are used in
foods. Antioxidants permitted by regulations for use in food were rigorously tested from
©Encyclopedia of Life Support Systems (EOLSS)
FOOD QUALITY AND STANDARDS – Vol. III - Additives and Contaminants - Natalia Cicic-Lasztiy
point of view of safety. The substances permitted for use in foods should be safe even at
excessive doses (at levels 100 times higher than the permitted limit). The total
concentration of antioxidants may be generally maximally 0.02% by weight based on
the fat content of food.
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The most frequently used synthetic antioxidants are monohydric and/or polyhydric
phenols with various ring substitutions. Such compounds are the butylated-hydroxianisol (BHA), butylated-hydroxi-toluene (BHT) (Fig.2.), tertiary-butyl – hydroxiquinone (TBHQ), and the propyl-gallate (PG). (Fig.3.).
Figure 2: Butylated –hydroxi-anisol and Butylated-hydroxi-toluene
Figure 3: Propyl gallate
Despite the officially declared safety, the general public concern with chemical
additives and food safety triggered a continuing search for new antioxidants that may
occur naturally in food or may form inadvertently during processing. At present only
tocopherol (vitamin-E) is used commercially as natural antioxidant, although a lot of
such compounds occur primarily in plants (including fruits and vegetables).
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Bibliography
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Belitz H., Grosch W., Schieberle P. (2004) Food Chemistry, Springer Verlag, Berlin-Heidelberg. [A book
recommended as textbook for students. The material is organized both according food constituents and
commodities. The comprehensive subject index makes easier the search of information needed]
Dombrowski W.M.,(2005) Toxins in Food. CRC Press Inc. Boca Raton. [A recent book based on critical
evaluation of research. Chemical properties, mode of action and biological effects of the toxins that occur
naturally in raw materials, and those resulting from inadequate processing or environmental
contamination]
Fennema O.R. (1985) Food Chemistry. Marcel Dekker, New York. [A widely used book for students in
food chemistry. A good review of generally used additives and a list of more than 200 additives including
chemical composition and field of use. A valuable source of information also for non specialists]
Otles S. (2005) Pesticide, Veterinary and other Residuesin Food. CRC Press, Boca Raton. [A recent book
concentrating on effect of use of chemicals in plant growing and animal husbandry on food
safety..Detction and surveillance methods are also treated]
Goodwin R.W.L. (1967 ) Chemical Additives in Food. J&J. Churchill Ltd., London. [An old but
interesting book. Particularly for reader interested in history and progress in this field. The knowledge and
views of specialists taking part in a consultation]
Weidenborner M. (2001) Encyclopediaof Food Mycotoxins. Springer Verlag, Berlin-Heidelberg.
[Relevant toxin-producing fungi, their natural occurrence, possible mycotoxicosis. For each mycotoxin,
there is an overview of the food at risk]
Biographical Sketch
Dr Natalia Cicic-Lásztity Ph.D. is a specialist in pediatrics at the Heim Pal Hospital in Budapest
Hungary. She received her M.Sc. degree from the University of Belgrade (Faculty of Medicine).in 1990.
Dr Cicic-Lasztity worked till 1997 in the Pediatric Clinic of Semmelweis University of Medical Sciences
in Budapest and obtained a degree of specialists in pediatrics. From 1998 to 2002 she takes part in
research program of the Hungarian Institute of Health and Nutrition connected with clinical nutrition of
patients with heavy pancreatitis. She received her Ph.D. degree in clinical nutrition in 2005. Dr CicicLasztity published several papers in scientific journals mainly in the field of clinical nutrition. She also
participated in several national and international scientific events. Her present major interest is enteral and
parenteral nutrition.
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